tbuckley/cabot-search huggingface dataset:
Abstract P2189: Role Of Innate Immune Response And Mitochondrial Ros In The Cardiac And Pulmonary Sequelae Of Covid-19
Authors: Ting Liu, Deepthi Ashok, Morgan Craney, Amanda Wong, D B Foster, Andrew Pekosz, Jason Villano, Brian O'Rourke
Journal: Circulation Research (2023)

Intro: Cardiac risk rises during acute SARS-CoV-2 infection and in long COVID syndrome, but the mechanisms behind COVID-19-linked arrhythmias are unknown. Here, we test the hypothesis that innate immune activation and mitochondrial ROS contribute to cardiac conduction abnormalities and pulmonary dysfunction in a COVID-19 hamster model. Results: ECGs and subpleural pressures were recorded by radiotelemetry over a 4-week timespan after SARS-CoV-2 infection. Multiple cardiac arrhythmias were observed, including bradycardia, sinus pauses, and atrioventricular block (AVB). RR intervals and sinus arrhythmia (RR&gt; mean+100ms, RR100) increased transiently 3-5 days after SARS-CoV-2 infection (baseline/peak: RR, 167±3ms/241±7ms; RR100, 5.5±0.4min -1 /22.7±3.0min -1 ) and returned to levels ≤ baseline by 7 dpi. After the acute phase, these measures increased above baseline over 3 weeks (at 28dpi: RR, 190±2ms, p&lt;0.05; RR100, 13.4±1.0 min -1 , p&lt;0.01). AVB count peaked at 3.1±0.1 min -1 at 1 dpi and gradually decreased to 0.4±0.2 min -1 by 28 dpi (vs. 0.004±0.002 at 0 dpi, p&lt;0.05). These parameters did not change in Mock-infected controls. RT-PCR showed that RIG-I, CXCL-10, OAS1, IL-1b and CCL-2 expression increased 18, 7, 2, 3, and 2-fold, respectively, over Mock controls at 4 dpi. IF analysis of the His-bundle region showed increased abundance of inflammatory IBA-1 + macrophages and decreased anti-inflammatory CD163 + macrophages. Ruxolitinib (Jak/Stat inhibitor) or mitochondrial antioxidant (mitoTEMPO) treatments were administered via implanted osmotic pumps. Subpleural pressure recordings indicated that infection induced tachypnea peaking at 7 dpi (272±11 versus 81±17 breaths/min at 0 dpi, p&lt;0.0001), which was attenuated by either treatment (peak: mitoTEMPO, 170±10; Ruxo,184±14). MitoTEMPO, but not Ruxolitinib, suppressed the increases in RR, RR100, and AVB during the acute phase and prevented the secondary changes in these measures in the post-acute phase (up to 28 dpi). Conclusions: The hamster model recapitulates a subset of arrhythmias observed in COVID-19 patients. Jak/Stat inhibition or mitoTEMPO treatment both mitigated acute respiratory distress, but only the latter suppressed arrhythmias during the acute and late phases of COVID-19.
Abstract P1158: Glucolipotoxicity Curtails Mitophagy In Cardiomyocytes
Authors: Younghee Hahn, Hongling Chen, Nidhi Banker, Srinidhi Gadula, Pravin Vathappallil, Brett Silverstein, Jennifer Van, Tamayo Kobayashi, Ziying Zhang, Yuan Huang, Qiangrong Liang, Satoru Kobayashi
Journal: Circulation Research (2023)

Diabetic patients suffer from complications of hyperglycemia and hyperlipidemia, which can lead to cardiovascular problems. The precise mechanism behind this phenomenon is unclear, but it is often associated with cellular damage and metabolic dysfunction. Mitochondria are responsible for energy production within cells, and abnormal metabolic conditions like diabetes can cause mitochondrial dysfunction. Mitophagy, the selective lysosomal degradation of damaged mitochondria, is a critical process for maintaining mitochondrial quality. However, the effects of hyperglycemia and hyperlipidemia on mitophagy in cardiomyocytes are not well characterized. We hypothesized that mitophagy is compromised in cardiac muscle cells by hyperglycemic and hyperlipidemic stresses. In this study, we investigated the effects of high-glucose (HG) and high-fat (HF) conditions on mitophagy in cardiomyocytes. We cultured H9C2 cardiac cells in media containing high levels of glucose (30 mM) and/or palmitate (25uM). The mitochondrial fractions were collected and the mitophagy flux was measured. Western blot analysis showed that the protein levels of microtubule-associated protein light chain 3 form II (LC3-II), a marker of mitophagosome, were reduced by HG and/or HF in either the absence or the presence of lysosomal inhibitors, suggesting inhibited mitophagy flux. The mitophagy flux was also determined by using dual fluorescent reporter that express mitochondria-targeted RFP-GFP fusion protein. Future studies will determine if HG and HF induce diabetic cardiac injury via impaired mitophagy.
Abstract P2025: Aminoacyl-trna Synthetase Complex-interacting Multifunctional Protein 3 (aimp3) Is A Key Regulator Of Cardiac Homeostasis
Authors: Anindhya S Das, Charles P Rabolli, Colton Martens, Federica Accornero
Journal: Circulation Research (2023)

In eukaryotes, a group of aminoacyl-tRNA synthetases evolved to form a complex thought to facilitate protein synthesis by efficiently providing charged tRNAs to the translating ribosome. The human muti-synthetase complex consists of 8 aminoacyl-tRNA synthetases and 3 non-enzymatic proteins known as aminoacyl-tRNA synthetase complex-interacting multifunctional proteins (AIMP1, 2, and 3). Aside from their role in translation, these multifunctional proteins are involved in other biological processes such as inflammation, apoptosis, and DNA damage response. However, their functions in specialized cells such as cardiomyocytes have not been studied. Here, we report that cardiomyocyte-specific conditional knockout (cKO) of AIMP3 in mice leads to lethal cardiomyopathy, which presents with severe systolic dysfunction, fibrosis, and inflammation. Cardiomyocytes from AIMP3 cKO mice show no change in global protein synthesis, suggesting that AIMP3 plays a critical translation-independent role. Proteomics and oxygen consumption analyses reveal a defect in mitochondrial activity and energy metabolism with ablation of AIMP3. Altogether, we highlight the importance of AIMP3 for the preservation of heart function.
Abstract P1025: Hsp70 Co-chaperones Regulate Sarcomeric Proteostasis In Hypertrophic Cardiomyopathy
Authors: Marcus J Wagner, Graham A Branscom, Liana T Alcaro, Jaime M Yob, Sharlene M Day
Journal: Circulation Research (2023)

Significance: Recent Genome Wide Association Studies (GWAS) identified non-sarcomeric variants in hypertrophic cardiomyopathy (HCM) with three of the top 10 variant loci in or near genes that encode for co-chaperones of HSP70: BAG3, DNAJC18 and HSPB7. These variants are also present in dilated cardiomyopathy (DCM), but have an opposing effect on cardiac function, leading us to hypothesize that GWAS variants in HSP70 co-chaperones can affect the proteostasis of contractile proteins in the HCM heart. As a first step, we determined the effects each HSP70 co-chaperone knockdown (KD) had on sarcomeric and z-disc protein expression and the poly-ubiquitinated state of cardiomyocyte-specific proteins. Methods and Results: Transduction of human iPSC-CMs (iPSC-CMs) with adenoviral vectors driving shRNA expression against BAG3, DNAJC18, HSPB7, or scramble (control) yielded transduction efficiencies &gt; 75% and &gt;80% reduction in target transcript 4 days post-transduction. BAG3 KD increased poly-ubiquitinated proteins by 38+/-9% (p&lt;0.001) and reduced steady state expression of sarcomeric and z-disc proteins, including: MyBP-C (p&lt;0.0001), actin (p&lt;0.0001), cardiac troponin I (p&lt;0.05), tropomyosin (TPM1) (p&lt;0.01), myosin light chain 3 (MYL3) (p&lt;0.0001), filamin C (p&lt;0.05), and alpha-actinin-2 (p&lt;0.0001). DNAJC18 KD increased poly-ubiquitinated protein by 66+/-17% (p&lt;0.01) but did not impact sarcomere protein expression. Conversely, HSPB7 KD reduced poly-ubiquitinated proteins by 21+/-7% (p&lt;0.01) and increased protein expression of MyBP-C (p&lt;0.01), TPM1 (p&lt;0.05), and myosin light chain 2 (p&lt;0.05). DNAJC18 KD increased BAG3 and HSPB7 protein expression levels by ~2-fold (p&lt;0.001) without increasing transcript levels, suggesting BAG3 and HSPB7 may be protein clients of DNAJC18. Conclusions: HSP70 co-chaperones that have an established genetic association with human HCM play an important role in cardiomyocyte proteostasis. Multiple sarcomeric and z-disc proteins appear to be clients of BAG3, while BAG3 and HSPB7 themselves may be clients of DNAJC18. Targeting this axis could be therapeutic for patients with HCM that possess genetic variants in sarcomeric proteins.
Abstract P1176: What Is The Nature Of The Hypertrophic Response Contributing To Pregnancy-induced Cardiac Growth And Its Reversal?
Authors: Helen E Collins, Emily Schulman
Journal: Circulation Research (2023)

During pregnancy, the maternal heart undergoes physiological cardiac growth, reversing following parturition; however, the contributing underlying processes are largely unknown. Changes in cardiac metabolism appear to be associated with cardiac growth through a reduction in glucose catabolism. We have also shown that several cardiac metabolic transcripts, proteins, and liver-derived metabolites that are elevated during pregnancy are associated with cardiac growth. However, the nature of the hypertrophic response observed in the maternal heart is unclear. Therefore, this study aimed to examine the metabolic and hypertrophic changes associated with pregnancy-induced cardiac growth and reversal. Studies revealed that both heart weight (HW: TL; p &lt; 0.0001) and liver weight (LIV: TL; p &lt;0.0001) were highest in lactating 1-week post-birth (PB) mice versus mid-pregnant (8 d), late-pregnant (LP; 16 d), and non-pregnant (NP) 12-week-old FVB/NJ mice. Of note, we also found that HW: TL ( p &lt; 0.01) and LIV: TL ( p &lt; 0.0001) were significantly reduced in non-lactating 1-week post-birth mice (PBNL) compared with PB mice. However, the changes in cardiac size observed during pregnancy and post-birth were not associated with changes in either cardiomyocyte cross-sectional area or cardiac fluid content. Hearts and livers remained significantly larger, irrespective of lactation status, following parturition through 6 weeks post birth (PB) versus NP. Consistent with these changes, we found significant reductions in Pdk4 protein between 1- and 3-week PB and PBNL groups that were reversed by six weeks postpartum and a substantial increase in Pdk4 expression at six weeks postpartum, respectively. Interestingly, we see a sustained increase in cardiac Bdh1 expression that persisted at six weeks postpartum, which could contribute to the sustained increases in HW: TL versus NP. Changes in lactation status and metabolism are likely contributing to similar patterns of growth seen in the heart and liver during and following pregnancy. The maternal hypertrophic response is considered eccentric due to the absence of changes in myocyte cross-sectional area and cardiac fluid content.
Abstract P2085: Growth Hormone Releasing Hormone Agonist Counteracts The Cardiometabolic Heart Failure With Preserved Ejection Fraction Phenotype In Vivo Via The Hypoxia Inducible Factor 1 Alpha
Authors: Rosemeire M Kanashiro-Takeuchi, Lauro Takeuchi, Wayne Balkan, Raul A Dulce, Katarzyna Kazmierczak, Shathiyah Kulandavelu, Renzhi Cai, Wei Sha, Andrew Schally, Joshua M Hare
Journal: Circulation Research (2023)

Heart failure (HF) with preserved ejection fraction (HFpEF) treatment is limited due in large part to a lack of understanding of the underlying mechanisms. Recently, we showed that growth hormone-releasing hormone-agonist (GHRH-agonist) has cardioprotective effects in a murine model of cardiometabolic HFpEF; however, the mechanism of these therapeutic effects is still unclear. Here, we hypothesize that the therapeutic effects of GHRH-agonist in HFpEF are mediated by GHRH-receptor activation of the hypoxia-induced factor (HIF)-1α pathway. Methods: Wild-type (WT) and HIF-1α cardiomyocyte knockout (HIF-1α CM KO) mice were fed a high-fat diet (HFD) plus the nitric oxide synthase inhibitor (L-NAME) for 9 weeks. After 5 weeks of HFD+L-NAME regimen, animals received daily injections of placebo or the GHRH-agonist, MR-356, for the remaining 4-week period. Control animals received no HFD+L-NAME or MR-356 treatment. Echocardiography, blood pressure, glucose tolerance test, and hemodynamic measurements were evaluated. Results: The HFD+L-NAME diet produced a HFpEF phenotype, which was reversed in mice with intact HIF-1α treated with MR-356. In contrast, in mice with a cardiac-specific deletion of HIF-1α CM , MR-356 treatment failed to reverse the elevated relative wall thickness in diastole (RWTd), increased E/E’ ratio and reduced global longitudinal strain (GLS). The slope of end-diastolic pressure-volume relationship (EDPVR) was increased in the placebo group and restored by MR-356 in WT mice but not HIF-1α CM KO mice, while EF was preserved. Conclusion: Our findings suggest that HIF-1α is necessary for the cardioprotective and anti-HFpEF effects MR-356.
Abstract P1124: Immunosuppression Drug Mediated Cardiovascular Effects
Authors: Ryan Dexheimer, Dilip Thomas, Sadhana Gaddam, Aly Elezaby, Ian Y Chen, Kevin Wang, Nazish Sayed, Karim Sallam
Journal: Circulation Research (2023)

Heart transplantation continues to be a life-saving therapy for patients with end-stage heart failure; yet the average long-term graft survival remains at only 12.5 years. Cardiac allograft vasculopathy (CAV) and cardiac graft dysfunction are both key contributors to long-term morbidity and mortality in the heart transplant population. Studies have suggested that immunosuppressive agents may modulate cardiovascular function, yet the mechanisms for this modulation is incompletely understood. The primary classes of immunosuppressive agents utilized post-heart transplantation are mammalian target of rapamycin inhibitors (e.g. sirolimus), calcineurin inhibitors (e.g. tacrolimus), and purine synthesis inhibitors (e.g. mycophenolate mofetil). Our prior findings indicate no discernible change to cell contraction or viability, but increased fibrosis and adverse remodeling in response to tacrolimus treatment. Using cardiac organoids; composed of human induced pluripotent stem cells (hiPSCs) derived cardiomyocytes, endothelial cells, and cardiac fibroblasts; we investigated the effects of these agents on the cardiovascular system using RNA-sequencing and proteomic analysis. Proteomic analysis of cardiac organoids was done using Luminex bead-array assay. Treatment with MPA coincided with a significant reduction of proinflammatory cytokines including the various interleukin-families and TNF-alpha/beta. Tacrolimus yielded mixed results on proteins associated with cardiac remodeling but indicated significant upregulation of proteins that have been implicated in CAV progression. In addition, RNA-sequencing findings revealed significant upregulation of genes associated with cardiac fibrosis and remodeling with tacrolimus treatment in comparison to sirolimus treatment. These findings correlate with functional profile observed on treatment of cardiac organoids. Our results provider further insight into the pathways by which differential immunosuppression drugs influence cardiovascular remodeling.
Abstract P1004: Cellular Heterogeneity In The <i>Nkx2.5</i> + Anterior Lateral Plate Mesoderm Underlies Lineage Diversity Of The Cardiovascular System
Authors: Hakan Coskun, Xinlei Gao, Kaifu Chen, C. Geoffrey Burns, Caroline Burns
Journal: Circulation Research (2023)

The cardiovascular system comprises diverse cellular lineages that emerge from progenitor cells in the anterior lateral plate mesoderm (ALPM). In zebrafish, nkx2.5 expression initiates in the bilateral field of ALPM progenitors during early somitogenesis before their spatial segregation into two main subpopulations. The cardiac fraction, including first (FHF) and second heart field (SHF) progenitors, migrates to the midline and gives rise to ventricular myocardium. The pharyngeal fraction remains lateral and sequesters in the cores of the pharyngeal arches (PAs). Progenitors in PA2 give rise to craniofacial muscles and three lineages in the outflow tract, while those in PA3-6 differentiate into pharyngeal arch artery (PAA) endothelium. The mechanisms underlying nkx2.5 + progenitor cell segregation into the various downstream fates remain unclear. Here, we demonstrate that nkx2.5 + progenitors in the ALPM are heterogenous with predetermined lineage outcomes. Specifically, single-cell RNA sequencing of nkx2.5:ZsYellow + progenitors revealed six transcriptionally unique populations, including a cardiomyocyte cluster (FHF-derived) and a large lateral plate mesoderm (LPM) population that further subclustered into three distinct groups. LPM-1 differentially expressed aplnra , hey1 , and the retinoic acid (RA)-eliminating enzyme cyp26c1 , LPM-2 expressed bmp4, bmp6 , and cdh11 , and LPM-3 expressed the transcriptional repressor prdm1a and the RA-producing enzymes rhd10a and aldh1a2 . In situ hybridization uncovered regionalization in the nkx2.5 + ALPM with LPM-1 cells occupying the anterior-medial and central region of the field and LPM-3 the posterior domain. Targeted photoconversion of nkx2.5:Kaede revealed that LPM-1 are PA2 progenitors while LPM-3 are progenitors for PA3-6. We are currently performing spatial transcriptomics to generate a comprehensive expression map of the ALPM, localizing and tracing LPM-2 progenitors, and performing functional studies that suggest a tbx1 -RA-prdm1a signaling pathway is required for LPM-3 specification. In conclusion, our data highlight progenitor heterogeneity in the ALPM as a source of the lineage diversification required to build the cardiovascular system.
Abstract P1034: Functional Modelling Of Arrhythmias With Human Cardiac Organoids
Authors: Mark Pocock, Rebecca Fitzsimmons, Mary Lor, Simon Foster, Michael R Doran, Richard J Mills, James E Hudson
Journal: Circulation Research (2023)

Engineered heart tissues (EHTs) have become a well-established model of human cardiac muscle. Metabolic maturity, improved sarcoplasmic reticulum (SR) Ca2+ handling, and the incorporation of critical non-myocyte cell populations are advantages that EHTs provide over immature 2D cardiomyocyte models. Our human cardiac organoid-EHT hybrid (hCO) platform was developed to be compatible with standardized 96-well tissue culture formats to enable high-throughput functional screening, while retaining the physiological advantages of larger EHTs. Here, we explored the applicability of hCOs as a model of various arrhythmic mechanisms. QT-prolongation could be mimicked with LTCC agonist BayK8644 or hERG blocker dofetilide, which increased the relaxation time of the hCOs and induced arrhythmia at high concentrations. Ectopy was induced by perturbing SR Ca2+ cycling with ryanodine or caffeine. HCN4 blocker ivabradine slowed rate, and at high concentrations produced a complex pause-burst phenotype. Increasing the cardiomyocyte-to-fibroblast ratio with growth factors, or the addition of extra fibroblasts prolonged contraction duration and induced ectopy. Inflammatory cytokines also increased relaxation time and provoked ectopy. From this data we propose that hCOs are a sensitive and reliable platform for studying arrhythmias and we are currently exploring the impact of CPVT-linked RYR2 and CASQ2 mutations on hCO arrhythmogenesis.
Abstract GS.11: Exercise Therapy During Doxorubicin Treatment Provides Sex-specific Cardioprotection
Authors: Lichao Tang, Paloma De Melo Amaral, Igor Efimov, Sharon Ann George
Journal: Circulation Research (2023)

Moderate-intensity exercise is routinely prescribed to patients with cardiovascular diseases to improve cardiac function. It has also been recommended in patients undergoing anti-cancer chemotherapy to attenuate cardiotoxic effects. We recently identified that moderate endurance exercise in healthy mice causes the remodeling of cardiac physiology in a sex-specific manner. Therefore, we hypothesized that exercise therapy applied during doxorubicin chemotherapy would produce sex-specific cardioprotection. Male and female mice were divided into three groups, 1) sedentary control, 2) DOX - doxorubicin treated at 5 mg/kg/week for 6 weeks, and 3) EXDOX - 2 weeks of forced treadmill running for 2 weeks before DOX + exercise for an additional 6 weeks. Mouse health was tracked daily. Total body weight, echocardiography, and electrocardiography were assessed every 2 weeks. At the end of the protocol, triple parametric optical mapping was performed to determine the remodeling of cardiac metabolism-excitation-contraction coupling (MECC). DOX treatment increased morbidity and reduced total body weight in both males and females. DOX-induced action potential duration (APD) prolongation in both sexes and, additionally, in males alone, increased anisotropic ratio of conduction (index for arrhythmogenicity) and rise time of calcium transients (CaRT). In EXDOX mice, the onset of morbidity was delayed in both males and females compared to DOX mice. Total body weight in male EXDOX mice, but not females, was further reduced compared to DOX treatment alone. Echocardiography revealed increased LV wall thickness in male and female EXDOX mice vs DOX, while stroke volume was reduced in females alone. Next, DOX-induced APD prolongation was prevented in EXDOX females but not males. Furthermore, DOX-induced increase in CaRT was further increased in EXDOX males, in addition to increased calcium transient duration and reduced calcium decay constant. Taken together, these data suggest significant sex dimorphism in cardiac adaptation to DOX treatment and exercise therapy during DOX treatment. Female mice undergoing exercise therapy during DOX treatment demonstrated greater cardioprotection and attenuation of MECC remodeling.
Abstract P2101: Elucidating Heterogeneity Between Left And Right Ventricle-derived Cardiac Fibroblasts
Authors: Michael B Dewar, Haisam Shah, Dylan Langburt, Fahad Ehsan, Alison Hacker, Scott P Heximer
Journal: Circulation Research (2023)

Cardiac fibrosis is a major risk factor for cardiovascular disease, leading to impaired electrical conduction and reduced ventricular compliance in the heart. Different pathophysiologic conditions can lead to fibrosis in the left ventricle (LV) and/or right ventricle (RV). Despite building evidence to support the transcriptomic heterogeneity of cardiac fibroblasts (CFs) in healthy and diseased states, there have been no direct comparisons of CFs in the LV and RV. Due to the developmental and physiologic differences between the two ventricles, we hypothesized that LV and RV-derived CFs would display transcriptomic differences that influence their proliferation and differentiation following injury. Bulk RNA-seq data from the LVs and RVs of uninjured male mice revealed 442 differentially expressed genes (p&lt;0.05, n=4) with numerous fibrosis-related genes such as Igfbp3 , Col8a1 , Ctgf , Aspn , and Postn being the most significantly different. Single-cell RNA-seq analysis of CFs from uninjured tissue identified nine subpopulations, two of which displayed LV vs RV differences. CFs marked by high expression of Postn , Col8a1 , and Ctgf were more abundant in the LV, whereas CFs marked by high expression of Igfbp3 , Fgl2 , and Sfrp2 were more abundant in the RV. Comparisons with published datasets suggest that Postn -high CFs are primed for differentiation into injury-induced CFs. While the Igfbp3 -high population has not previously been described, top marker genes have mixed pro- and anti-fibrotic roles. We then used surgical models of pressure overload injury (TAC and PAB) to study changes in the transcriptome of LV and RV-derived CFs respectively at 14 days post-surgery. Single cell RNA-seq analysis showed that the LV developed a larger population of pro-fibrotic Thbs4 +/ Cthrc1 + injury-induced CFs while the RV uniquely showed expansion of Igfbp3 - and Inmt -high CFs. Injury experiments were repeated with female mice and showed the same results. These findings demonstrate that LV and RV-derived CFs display subpopulation differences that may cause their diverging responses to pressure overload injury. Further study of these subpopulations will elucidate their role in the development of fibrosis and inform whether LV and RV fibrosis require distinct treatments.